We compared the histological changes before and
after treatment in 14 cases of
myeloperoxidase antineutrophil cytoplasmic
autoantibodies (MPO-
ANCA) related
nephritis in whom we were able to perform two renal biopsies. The results show that the clinical findings and acute glomerular and tubulointerstitial
injuries decreased, while chronic glomerular
injuries increased. No changes were seen in minor glomerular abnormalities(MGAs) or chronic tubulointerstitial
injuries between the first and second biopsies. In the vascular system, no treatment related aggravation of
arteriosclerosis occurred and it was found that fibrinoid
necrosis disappeared with treatment. Finally, in MPO-
ANCA related
nephritis, the care given between the first and second biopsies caused acute glomerular
injuries to become chronic glomerular
injuries, but no changes were detected in the MGA. We believe that the changes in acute tubulointerstitial
injuries reflected an improvement in renal function, since the acute tubulointerstitial
injuries obviously improved in response to PSL, contributing to the improved renal function. In other words, MPO
ANCA-related
nephritis is a condition that involves "acute glomerulonephritis+
acute tubulointerstitial nephritis +
angiitis," and it is thought that the characteristics of each are independent. We believe that the renal function improved as the
acute tubulointerstitial nephritis improved, while the acute glomerular
injuries developed into chronic glomerular
injuries.